Hello,
indeed this can sometimes be a problem, the solution for the moment is simply to do an "Alt" + "Enter" to put the game in window mode, then move the window to the desired screen with the mouse and then redo an "Alt" + "Enter" to return the game to full screen. Then, during the next launches, the game should systematically launch on the correct screen.
I hope I was able to help you and I will try to integrate the possibility of choosing your screen in the next update.
Thank you, take care of yourself.